It's an interesting way to say something that seems obvious: to the extent that humans believe they're being watched, or judged, by some sort of more powerful entity, they'll behave better.* And that has evolutionary benefit. The tendency to believe in god/gods evolved in us, for obvious reasons, and it's powerful enough that it exists, with all its internal contradictions (I'm thinking of the biblical god in particular: polytheism gets around a lot of the problems), in otherwise very critical thinkers.
DNA: all knowing, all powerful!
* Somewhere back in the archive is a post I wrote about an experiment: in an employee lounge there was a place for free coffee, and a request for donations to cover the cost. Above the area were placed differing pictures. When it was generic, landscape, whatever, people gave donations at a much lower level than when there was a picture of two large eyes looking back. (I tried to find the post, and failed; but I did stumble upon this one, which I found re-amusing. Sometimes I crack myself up.